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AAOS Now

Published 10/1/2008

Second Look – Clinical News and Views

If you missed these Headline News Now items the first time around, AAOS Now gives you a second chance to review them. Headline News Now—the AAOS thrice-weekly, online update of news of interest to orthopaedic surgeons—brings you the latest on clinical, socioeconomic, and political issues, as well as important announcements from AAOS.

Modified MRI may detect early OA

New imaging technology may provide physicians with a test for early diagnosis of osteoarthritis (OA), according to a presentation at the national meeting of the American Chemical Society. The technology uses a modified form of magnetic resonance imaging (MRI) to determine the concentration of glycosaminoglycan (GAG), which is a recognized biomarker for both OA and degenerative disk disease. A low concentration of GAG is known to correlate with the onset of OA and other cartilage disorders.

Proton pump inhibitors increase risk of osteoporotic fractures

Patients who use proton pump inhibitors for 7 or more years to treat reflux, peptic ulcers, and other conditions are at greater risk of osteoporosis-related fractures, according to a study published in the Canadian Medical Association Journal. The authors used administrative claims data to identify patients with a fracture of the hip, vertebra, or wrist between April 1996 and March 2004. They matched 15,792 cases of osteoporosis-related fractures with 47,289 controls. The researchers found an increased risk of hip fracture after 5 years of continuous exposure to proton pump inhibitors, with an even higher risk after 7 years of exposure. An increased risk of any fracture was found after 7 years of continuous exposure. Short-term exposure did not appear to increase risk of fractures.

Engineers create artificial bone that blends into tendons
According to a
study published in the Proceedings of the National Academy of Sciences, Engineers at Georgia Tech have used skin cells to create artificial bones that mimic the ability of natural bone to blend into other tissues such as tendons or ligaments. The artificial bones display a gradual change from bone to softer tissue, providing better integration with the body and allowing the bone to handle weight more successfully. The researchers created the tissue by coating a three-dimensional polymer scaffold with a gene delivery vehicle that encodes the Runx2 transcription factor. By concentrating a high amount of Runx2 at one end of the scaffold and decreasing that amount until they ended up with no transcription factor on the other end, they generated a precisely controlled spatial gradient of Runx2. Skin fibroblasts seeded uniformly on the scaffold turned into bone where there was a high concentration of Runx2, while the skin cells on the scaffold end with no Runx2 turned into soft tissue.

Bone density testing in some older patients could be delayed to once every 5 years

According to findings published in the Canadian Medical Association Journal, repeat bone density testing in middle-aged and older adults can be delayed for intervals of up to 5 years if they don’t have risk factors for bone loss. The authors examined a longitudinal cohort of 9,423 participants and measured the bone mineral density in the lumbar spine, total hip, and femoral neck at baseline and at 3-year and 5-year follow-up visits. They found that bone loss in all three skeletal sites began among women at age 40 to 44 years and was greatest among women aged 50 to 54 who were transitioning from premenopause to postmenopause. The change from baseline was –6.8 percent over 5 years. The rate of decline, particularly in the total hip, increased again among women older than 70 years. Bone loss in all three skeletal sites began at an earlier age (25–39 years) among men than among women. The rate of decline of bone density in the total hip was nearly constant among men age 35 years and older, increasing again among men older than age 65 years.

Nearly one in five stop taking osteoporosis drug at “doughnut hole”

A report released by the Kaiser Family Foundation examines the effect of the so-called Medicare Part D “doughnut hole”—a gap in Part D coverage that is reached after an enrollee has incurred $2,510 in total drug costs for the year. Among Part D enrollees taking an osteoporosis medication, the report finds that 18 percent stopped taking that medication upon reaching the doughnut hole. When this gap is reached, the patient becomes responsible for 100 percent of medication costs until his or her annual drug expenses reach $5,726, at which time Medicare picks up 95 percent of additional medication costs. Approximately one in four Part D enrollees who filled any prescription in 2007 reached the gap.

Women at low risk for VTE may stop anticoagulant therapy after 6 months

A study published in the Canadian Medical Association Journal suggests that women who have 0 or 1 risk factors for venous thromboembolism (VTE) may safely discontinue oral anticoagulant therapy after 6 months of therapy following a first unprovoked VTE. The research team conducted a multicenter prospective cohort study of 600 participants who had an unprovoked major VTE and completed a mean 18-month follow-up. They identified 91 confirmed episodes of recurrent VTE during follow-up after discontinuing oral anticoagulation therapy. Among male patients, the researchers found no combination of clinical predictors that satisfied their criteria for identifying a low-risk subgroup. Among female patients, however, researchers found that 52 percent had 0 or 1 of the following characteristics: hyperpigmentation, edema or redness of either leg; D-dimer 250 µg/L while taking warfarin; body mass index 30 kg/m2; or age 65 years. These women had an annual risk of 1.6 percent; women who had two or more of these findings had an annual risk of 14.1 percent.

Study links HIV to increased incidence of fracture

A study published online in the Journal of Clinical Endocrinology and Metabolism finds that patients who are positive for human immunodeficiency virus (HIV) have a higher rate of fractures than patients who are HIV-negative. The authors conducted a population-based study of 8,525 HIV-infected and 2,208,792 non–HIV-infected patients with at least one inpatient or outpatient encounter between Oct. 1, 1996, and March 21, 2008. The overall fracture prevalence was 2.87 per 100 persons in the HIV-infected group, compared to 1.77 per 100 persons in non–HIV-infected patients. Among women, overall fracture prevalence was 2.49 per 100 (HIV-infected) versus 1.72 per 100 (non–HIV-infected). HIV-infected female patients had a higher prevalence of vertebral (0.81 vs. 0.45) and wrist (1.31 vs. 0.83) fractures per 100 persons compared to non–HIV-infected females, but had a similar prevalence of hip fractures (0.47 vs. 0.56). Among males, fracture prevalence per 100 persons was 3.08 per 100 (HIV-infected) versus 1.83 per 100 (non–HIV-infected) for any fracture, vertebral fractures (1.03 vs. 0.49), hip fractures (0.79 vs. 0.45), and wrist fractures.

Study: Compression stockings often misused

A study in the American Journal of Nursing finds that compression stockings are often used and sized incorrectly. The authors conducted a comparative, descriptive study of 142 hospitalized postoperative patients (119 women and 23 men, mean age of 57 years). Overall, 37 patients had thigh-length and 105 had knee-length stockings. To be eligible for inclusion in the study, patients had to have had surgery within the previous 14 days, have a physician’s order for graduated compression stockings, have the stockings in place at the time of the study, and be in stable condition. The researchers assessed patients’ skin, compared leg measurements to the manufacturer’s sizing chart, and asked patients to rate the comfort of the stockings and to describe their purpose. They found that the stockings were used incorrectly in 29 percent of the patients and sized incorrectly in 26 percent of the patients.